TM 5-3805-260-24
location of the components that are worn, or not working
correctly. Not all probable reasons have an application
to all machines.
PROBLEM: Setting of the relief valve is higher or
lower than given in Test 1. Percent of
flow loss for Tests 4 and 5 is 15% to
50%.
PROBABLE REASON:
Setting for relief valve is not correct and leakage is too
high.
RECOMMENDATION FOR ACTION:
Make adjustments to the relief valve to get the correct
pressure. See the Service Manual for the machine
under test. Make a test for leakage in the following
problems.
PROBLEM: Percent of flow loss for Tests 4 and 5 is
15% or MORE.
PROBABLE REASON:
A. Bad pump.
B. Leakage in the relief valve.
C. Leakage in one or both of the piston seals for the
steering cylinders.
D. Wear or damage in the valve body or valve spool.
E. Hand metering pump, unloading valve, selector
valve or diverter valve is worn or not working
correctly.
RECOMMENDATION FOR ACTION:
A. Do the Pump Test.
B. If the extra percent of flow loss is not caused by a
bad pump, the problem is in the control valve or
cylinders. Do the Blocked Cylinder Tests 26, 27
and 28. If the leakage is still too high, the
problem is in the control valve. Inspect its
components.
PROBLEM: Percent of flow loss for Test 4 is 15% or
MORE; for Test 5 it is 0 to 15%.
PROBABLE REASON:
A. Wear or damage in the valve body or valve spool.
B. Adjustment of follow-up linkage is not correct.
C. Unloading valve or relief valve does not move
freelv.
RECOMMENDATION FOR ACTION:
The problem is in the control valve or linkage.
Inspect these components.
PROBLEM: Percent of flow loss for Test 5 is 15% or
MORE; for Test 4 it is 0 to 15%.
PROBABLE REASON:
A. Wear or damage in the valve body or valve spool.
B. Adjustment of follow-up linkage is not correct.
C. Unloading valve or relief valve does not move
freely.
RECOMMENDATION FOR ACTION:
The problem is in the control valve or linkage. Inspect
these components.
PUMP TEST (CHART B)
This test is used to find the efficiency of the hydraulic
pump. Install a Blocking Plate Assembly in the return
line on the control valve. This prevents oil from going
through the system. All pump flow now goes through the
flow meter.
NOTE: Make sure the brake accumulator is not
operating while taking test data.
WARNING: Open the manual load valve on L .
the flow meter fully before starting the diesel engine.
The relief valve is not part of the circuit for the Pump
Test. If the pressure gets too high, it is possible to
cause injury to personnel or damage to equipment.
Test 14: Pump Flow at Low Pressure (test rpm)
1. Open the manual load valve fully.
2. Start the diesel engine.
3. Run the engine at test rpm.
4. Slowly close the manual load valve to get 100 psi
pressure.
5. Write down the oil temperature and flow rate
(gpm).
2-120
